Recently, in the field of graphic arts, for labor-saving. rationalization and improvement of working conditions, a technology has been required for switching from the conventional dark room film making, the so-called contacting process, over to a day-light film making, and many improvements have been done about equipment of photographic light-sensitive materials and printers.
The photographic light-sensitive materials, which may be handled in day-light room, include those photosensitive to a light source emitting ample UV rays, such as a ultra high pressure mercury lamp, a metal halide light source, a xenon lamp, and a halogen lamp. These silver halide photographic light-sensitive materials can be handled under a normal fluorescent lamp as bright as 100 to 300 lux or a fluorescent lamp for exclusive use from which emits a small quantity of UV rays.
While these photographic light-sensitive materials, which contain a hydrazine or tetrazolium compound for producing ultra-high contrast images have such merits, they have the disadvantage that they are liable to produce the so-called pin-hole trouble in blackened images after they are developed.
The term, pin-hole, herein means a phenomenon that a white spot having a size of about 30 .mu.m or smaller is produced in a blackened image. As the spot has a circular or amorphous shape and it looks as if it were made by piercing with a pin, so it has been named so.
Fidelity of halftone image reproduction cannot be obtained in a contact printing process, if the film for contact process itself has abnormal blackened dots caused by `pin-hole`. Therefore, the produced pin-holes must be prevented by making them opaque, so that the operation efficiency has been remarkably worsened. There has been one of the countermeasures in which any compound having an absorption in a wavelength region longer than that of silver halide shall not be contained in the film. In this measure, however, the film cannot be handled in bright working conditions and the merits of day light operation is diminished.
For such present condition, there have been strong demands for a day light film in which pin-hole are hardly produced.